When Rok Ma first met the Tenth Doctor, his team had taken control of Elvis the King Spaceport. He assisted the Doctor and Nikki Jupiter in bringing down the criminal underworld of New Memphis. After the investigation finished, he stayed with Nikki and joined her Detective Agency. (PROSE: Judgement of the Judoon)
Rok Ma was a typical Judoon when he first met the Doctor, but as he spent more time with him he became more understanding of the human mind. His personality changed so he was happier and less fixated on Judoon justice.